Simplify the following expression: $k = \dfrac{4c}{2c} - \dfrac{4c - 6a}{2c}$ You can assume $a,b,c \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{4c - (4c - 6a)}{2c}$ $k = \dfrac{6a}{2c}$ The numerator and denominator have a common factor of $2$, so we can simplify $k = \dfrac{3a}{c}$